Flame-resistant organic textiles through treatment with halogen containing soluble methylol phosphine adducts

ABSTRACT

SOLUBLE METHYLOL PHOSPHINE ADDUCTS WHICH CONTAIN HALOGEN ATOMS ATTACHED TO AROMATIC CARBON ATOMS ARE PREPARED BY REACTING TRIS(HYDROXYMETHYL)PHOSPHINE WITH HALOGEN SUBSTITUTED PHENOLS WHICH CONTAIN ONE OR MORE HYDROGENS ORTHO OR PARA TO THE PHENOLIC HYDROXYL GROUP. THESE ADDUCTS ARE CONVENIENT AND USEFUL FOR (A) THE PREPARATION OF FLAMES-RESISTANT POLYMERS AND (B) THE PREPARATION OF FLAME-RESISTANT ORGANIC FIBROUS MATERIALS AND FLAME-, GLOW-, WRINKLE-, AND SHRINK-RESISTANT WOVEN AND KNIT TEXTILES WHICH CONTAIN ABOUT 25% OR MORE CELLULOSIC FIBERS.

United States Patent 3,745,191 FLAME-RESISTANT ORGANIC TEXTILES THROUGH TREATMENT WITH HALO- GEN CONTAINING SOLUBLE METH- YLOL PHOSPHDJE ADDUCTS Donald J. Daigle, New (Means, and Wilson S. Reeves and George L. Drake, .ln, Metairie, La., assiguors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed May 7, 1971, Ser. No. 141,447 Int. Cl. C07f 9/50 US. Cl. 260--606.5 P 6 Claims ABSTRACT OF THE DISCLOSURE Soluble methylol phosphine adducts which contain halogen atoms attached to aromatic carbon atomsare prepared by reacting tris (hydroxyme'thyDphosphine Wl'th halogen substituted phenols which contain one or more hydrogens ortho or para to the phenolic hydroxyl group. These adducts are convenient and useful for (a) the preparation of flame-resistant polymers and (b) the preparation of flameand glow-resistant organic fibrous materials and fiame-, glow-, wrinkle-, and shrink-resistant woven and knit textiles which contain about 25% or more cellulosic fibers.

A non-execlusive, irrevocable, royalty-free license in the invention herein described, throughout the World for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to new halogen and phosphorus containing compounds; to halogen, phosphorus, and nitrogen containing polymers; and to processes for their use in the production of flame-resistant organic fibrous material. More specifically, it deals with a method of producing halogen containing soluble methylol phosphine adducts and the use of these to produce insoluble polymers and flame-resistant organic fibrous products through reaction of the adduct with nitrogenous compounds.

As employed throughout the specifications and claims of this invention, the term THP refers to the compound tris(hydroxymethyl)phosphine. The term halogen containing methylol phosphine adduct refers to soluble compounds produced by reacting THP with certain halogen containing phenolic compounds.

Copending application by Daigle, Reeves, and Drake filed of even date relates to the production and use of polymers made by reacting THP with hydroxy benzenes of the group consisting of phenol halo hydroxyl, and alkyl substituted phenols in which hydrogen atoms are attached to at least two ring carbon atoms which are ortha or para to a hydroxyl group.

Copending application by Reeves, Daigle, Donaldson, and Drake filed of even date relates to soluble methylol phosphine adducts prepared by reacting THP with a monomeric nitrogenous compound which contains at least one member of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms.

A primary object of the present invention is to provide soluble methylol phosphine adducts which contain halogen atoms attached to aromatic carbon atoms which adducts are capable of further reaction with certain nitrogenous agents to produce thermosetting flame-resistant polymers and flame-resistant organic fibrous materials.

We have now discovered that THP reacts with monomeric halogen containing phenolic compounds which contain one or more hydrogen atoms attached to ring carbons at ortho and para positions to the phenolic group to produce soluble halogen containing methylol phosphine adducts. We have also discovered that these adducts can be further reacted with nitrogenous compounds which conice tain at least two members of the group hydrogen atoms and methylol radicals attached to trivalent nitrogen to produce flame-resistant polymers and flameand wrinkleresistant textile products.

More specifically, the products and processes of our invention may be described as follows: (1) Soluble halogen containing methylol phosphine adducts are made in solution which have a pH from about 7 to 8 by reacting THP with an essentially monomeric halogenated phenol which has at least one hydrogen attached to a ring carbon, ortho or para to the phenolic hydroxy group. In order to make the soluble and useful adducts of this invention, there must be an excess of methylol phosphorus radicals (PCH OH) in the adduct. For purposes of the reaction, THP is trifunctional; the functionality of the halogenated phenol is determined by the number of hydrogens attached to aromatic carbons ortho or para to the phenolic OH group. The adducts of this invention are essentially materials which contain the structures of the group consisting of (HO CHz) P OH;

where m and n are integers of 1 or 2 and the sum of m+n is 3. (2) To produce thermosetting polymers in accordance with this invention the halogen containing methylol phosphine adduct is reacted with a nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms. The reaction is carried out by dissolving the halogen containing methylol phosphine adduct and the nitrogenous compound in a suitable medium and then heating as needed until a viscous solution and finally a solid polymer is produced. Polymers produced by this process are insoluble, thermosetting, and flame resistant. The polymers contain a reoccurring trimethylene phosphorus radical (PCH which can be oxidized to a trimethylene phosphine oxide structure'OP(CH (3) To produce flame resistant organic textiles by a heat cure process the textile structure is wetted with a solution containing the methylol phosphorus adduct and a nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms, then drying and heating the textile at a temperature ranging from about to C. for a period of time necessary to promote copolymerization of the methylol phosphine adduct and the nitrogenous agent within or on the textile structure. (4) To produce flame resistant organic textiles by an ammonia cure process, the textile structure is Wetted with a solution containing the methylol phosphine adduct then the textile is dried and finally the dried textile is exposed to ammonia or amine gas. The amount of ammonia or amine applied to the dried textile is suflicient to react with substantially all of the P methylol radicals. One ammonia atom is capable of reacting with three P methylol radicals. The resulting product is insoluble in essentially all solvents and the flame resistant product formed in the textile is resistant to laundering and drycleaning.

Halophenolic compounds suitable for use in making soluble adducts of this invention include ortho halophenol, meta halophenol, para halophenol, ortho halophenetole, halophenylphenol, and haloresorcinols. The primary requirement for the halophenol is that it contain at least one hydrogen attached to a ring carbon atom which is ortho or para to a phenolic hydroxyl group. The proper molar ratios of the THP and the halophenolic compound to be used in making soluble adducts is such that the number of methylol phosphorus radicals is greater than the number of hydrogens attached to ring carbons ortho or para to phenolic hydroxyl groups. Preferably one phenolic molecule will be reacted with one THP molecule.

Solvents suitable for use in preparing the methylol phosphine adducts of this invention include dimethylformamide, alcohols such as methanol, ethanol, and isopropanol, and water and mixtures of these compounds. The amount of solvent can be varied as desired. The adducts are used in solution, therefore, it is not necessary to isolate them. Catalysts are not necessary for conducting this reaction. However, it is particularly desirable to maintain pH of the system from about 7 to about 8.

Suitable nitrogenous compounds for use with the halo gen containing methylol phosphine adducts in the production of thermosetting polymers include virtually any soluble nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and. methylol radicals attached to trivalent nitrogen atoms. Examples of suitable amides include urea, thiourea, melamine, cyanamide, ethyleneurea, propyleneurea, dicyandiamide, hydroxyethylcarbamate, octadecamide, acrylamide, amino acids, methylol and alkylated methylol derivatives of these amides. Examples of suitable amines include ethylamine, methylamine, ethylenediamine, ammonia, analine, and cetylamine. Mixtures of these amides and amines can suitably be employed. Thermosetting polymers are principally prepared by agitating a mixture of the adduct and the nitrogen compound or compounds in a solvent system while heating until copolymerization occurs. The preferred relative amounts of methylol phosphine adduct and nitrogen compounds used to copolymerize can be calculated by conventional methods for condensation polymerization reactions assuming that the functionality of the adduct equals the number of methylol phosphorus radicals on the adduct and that the functionality of the nitrogenous agent is equal to the sum of the number of hydrogens nd methylol radicals attached to trivalent nitrogen. Useful products may contain as little as about one mole of the soluble adduct per ten moles of nitrogenous compounds. The use of small quantities of the adduct with large quantities of the nitrogenous compound is made practical when the nitrogenous compound contains N-methylol radicals (N-CH OH) which permit the compounds to form condensation polymers even in the absence of the soluble methylol phosphine adduct. The maximum proportions of the soluble adduct that may be used with a nitrogenous compound for the production of useful polymers is about one mole of the adduct per mole of the nitrogenous compound.

In the production of flame-resistant organic fibrous materials by a heat cure process, the fibrous structure is wetted with a solution containing the soluble adduct and the nitrogenous agent; it is then passed through squeeze rolls to remove excess liquid. The structure is then dried and heated from about 110 to about 160 C. The pH of this treating solution may range from about 3 up to about 7.5. It is generally desirable for the treating solution to contain an acid producing catalyst such as zinc nitrate, magnesium chloride, hydrochloric amid, ammonium chloride, or a mixture of magnesium chloride and an organic acid such as citric acid. The amount of acid catalyst needed may be varied from about 0.5 percent up to about three percent based on the weight of the solution. The concentration of the adduct and the nitrogenous agent in the treating solution can be varied depending upon the amount of flame resistance to be imparted to the organic fibrous structure. Even one or two percent of the adduct and nitrogenous agent produces marked changes in the burning characteristics of the treated textile structure. Where complete flame resistance is to be contributed, about to 20 weight percent must be applied to the textile structure.

In the treatment of organic fibrous structures by the ammonia cure process, the textile structure is wetted with a solution of the halogen containing soluble methylol phosphine adduct, then the fabric is dried at a temperature ranging between about 70 C. and 120 C. Finally, the fabric structure is exposed to ammonia gas for' a few seconds, generally from two to fifteen seconds. The time of the exposure to ammonia is not so important as the amount of ammonia applied to the fabric. The amount of ammonia applied should be adequate to react with essentially all of the P methylol radicals. If desired, one can complete the insolubilization of the adduct by first exposing the dry fabric to NH gas for about 2 to 10 seconds then passing the fabric through a dilute solution of ammonium hydroxide. However, this order of treatment cannot be reversed. While ammonia is the most convenient nitrogenous gaseous product for use in this chemical cure, other amines may also be used, particularly methylamine and ethylamine. A preferred procedure for treating the textile structure with the amine is to force ammonia gas or methylamine through the textile structure. In his manner, reaction can be completed within one to three seconds.

Virtually any fibrous organic product capable of being impregnated with the soluble adduct can be made flame resistant by use of this invention. Textiles suitable for use in this invention are woven, knit, or nonwoven structures. For best results, the textile structure should contain at least about 25% of a cellulosic fiber. Cellulosic fibers suitable for use in this invention include, cotton, rayon, ramie, fiax, and the like fibers. Various noncellulosic natural fibers can also be used in this invention, such as wool and mohair. Noncellulosic synthetic fibers suitable for use in this invention along with a cellulosic fiber are polyesters, nylons, acrylics, polyvinylchlorise, and the like fibers. When cellulosic fibers are blended with flammable noncellulosic fibers it is preferable to have about 50% or more cellulosic fiber in the blend structure.

The following example is illustrative of the invention:

EXAMPLE 1 Soluble methylol phosphine adducts containing phosphorus and halogen were prepared by reacting THP (melting point about 58 C.) with a halogenated phenol as exemplified in Table I. These stable adducts were put into solution with an amine or amide to produce copolymer solutions as shown in Table II. One of the adducts was put in fabric by a padding process, then the fabric was dried and exposed to NH gas for a few seconds to insolubilize the adduct in or on the fabric as shown in Table III. Aliquots of the copolymer solutions from Table II were also applied to fabric by the padding technique. These fabrics were either heated at elevated temperatures or exposed to NH, gas to form insoluble flame retardants in or on the cotton as described in Table III. Parts of each fabric from Table III were laundered then examined. All samples exhibited a significant degree of flame resistance. The copolymer solutions of Table II were polymerized as described in Table IV to produce insoluble thermosetting flame resistant products.

TABLE I.PREPARATION OF SOLUBLE METHYLOL PHOSPHINE ADDUCTS CONTAINING HALOGEN AND PHOSPHORUS 77-2 41.3 g. (.33 mole) THP, 29 g. (.165 mole) Heated at 60 C.

p-bromophenol, g. isopropyl alcofor 30 min. hol (about 39% solids in solution). then cooled.

TABLE II.-PREPARATION OF COPOLYMER SOLUTIONS FROM SOLUBLE ADDUCT AND AMIDES OR AMINES 6 We claim: 1. A process for producing a soluble methylol phosg ggg i Amide or mine added to phine adduct containing a halogen atom attached to an designation a uct mtio e adduct aromatic phenolic nucleus and containing also an excess 77-3 M of adduct: 77-1 which 2.7 g. ethylenediamine (.082 5 of f p Phosphorus radlcals (PCHZOHL compnsutg h h i ()g 1 more) and 63 g isopropyl reacting, 1n the presenceor absence of formaldehyde, tr1s 131E561? 2 1253583? alum!" (hydroxymethynphosphme with an essentially monoalcohol. meric, halogen-containing phenolic compound having at -g g g% gg Wanaleast one hydrogen atom attached to a ring carbon atom 77 M of adduet 77-2 which 5.1 g. urea in 9 mi. 11 0 at a POSIUOII 0rfl10 0r P t0 the Phenolic Y Y p, i g fi gfgfifiga by heating and agitating a solution containing at least an '2 isopropyl n h r equimolar to a molar errcess of said tris(hydroxymethyl) gf gg g igg tl figggg fi phosphine relative to said phenolic compound so that the yioiureacontained on the number of methylol phosphorus radicals is greater than averagel-limethylolgroups 15 the number of hydrogen atoms attached to ring carbon per urea molecule.)

atoms ortho or para to the phenolic hydroxyl group thereby providing an excess of methylol phosphorus radicals (PCH OH) in the resulting adduct.

TABLE IIL-PREPARATION OF FLAME RESISTANT TEXTILES THROUGH USE OF SOLUBLE HALOGEN CONTAINING METHYLOL PHOSPHINE ADDUCTS Adduct or Approximate Properties of treated fabric copolymer add-on of resolution Conditions for detardant after Match Afterapplied to positing insoluble the treated test glow, Fabric treated fabric polymer in fabric textile Hand Strength Color angle sec. 50/50 polyester/cotton blend 77%: NH; gas for 6 min 17.1 Good Good" White. 180 2 Cotton sheeting 77-5 Heat, 150, 3 min 9. 4 0. do. do. 90 2 Do 77-6 .do 12.5 .do do (10.. 110 2 Do 77-2 NH3 gas for 1 min do do. do 100 2 TABLE IV.PREPARATION OF INSOLUBLE THERMO GLOW RESISTANT POLYMERS THROUGH USE OF SOLUBLE ADDUCTS AND AMINES SETTING FLAME AND OR AMIDES 2. The process of claim 1 wherein tris(hydroxymethyl phosphine is reacted with para-bromophenol in aqueousalcoholic solution at a temperature of about from 40 to 80 C.

3. The process of claim 1 wherein tris(hydroxymethyl) phosphine is reacted with ortho-bromophenol in aqueous- Time required to alcoholic solution at a temperature of about from to o 1 il i i? O 0 me! 6 IIISOU e sol tid n reaction, product, 4. The product produced by the process of claim 1. used mmutes Nature Polymer 5. The product produced by the process of claim 2. 77-3 25 20 White, insolubleinHzO,acid and 40 6. The roduct produced by the process of claim 3.

alkag. gorfied withiriI ZOtmin Y??? 3115 31; 32%;? g?) References Cited 20 u e n gci an aiiiii". 110113 11 33; UNITED STATES PATENTS ali n? 32 51 5253 r3535 4r 2,995,551 8/1961 Reuter et al. 260-6065 PX black char. 1 gtgg ggggggg 55 3i" gg WERTEN F. w. BELLAMY, Primary Examiner 77-6 10 White, insoluble in 1120. Flame CL resistant and forms black char. 

